Bats focus of county's attention
January 13, 2023
Twelve years ago, the death of a bat during a logging operation in Carlton County would not have caused much of a stir. Today - after white-nose syndrome has decimated bat populations here by as much as 90 percent - the death of one bat could impact the health of the entire population.
"Prior to white-nose, if a bat was injured, it was one of thousands. It didn't make a big dent in the population," said Carlton County land commissioner Greg Bernu. "We want to make sure we don't accidently take a juvenile bat that may be the future of these bats, that may have that chromosome that makes them immune to the disease."
White-nose syndrome - first documented in Minnesota in winter 2011-12 - is caused by a fungus that prospers in cave environments, where bats winter. The fungus is believed to cause bats to rouse from their winter hibernation, usually to seek insects for food, thinking it's later in the season. While searching for insects or other food, the bats end up depleting their body fat, which is often fatal. The bats face extinction due to the wide-ranging impacts of the disease, which has no cure.
As land manager, Bernu manages county-owned forest lands, which are often tax-forfeited properties. He also coordinates logging bids on those lands. His position, and serendipity - in the form of an Enbridge bat study outside his office a decade ago - led to a first-of-its-kind habitat conservation plan with Aitkin County.
"Enbridge came through to survey for the Sandpiper pipeline - and they actually had nets outside our building," Bernu said. "I asked what they were doing. They brought us out and we caught some bats. It was kinda cool."
Bernu knew white-nose syndrome was killing bats out east, and he knew the disease was headed this way. His colleague in Aitkin County, Mark Jacobs, and Kathryn Fernholz of Dovetail Partners, a Minneapolis-based natural resources think tank, were already talking about bats.
When Bernu called, the three decided to work together to learn more about the who, what and where of local bat populations, an eight-year process.
At the same time, they also wanted to get out ahead of any U.S. Fish and Wildlife Service endangered listing with a local solution.
The plan - approved by county commissioners and the federal government - should protect the remaining bats, and also ensure that logging on county-managed lands can continue, within specific guidelines. The plan focuses on three different at-risk bat species: northern long-eared (declared endangered on Nov. 29), little brown, and tri-colored bats.
Trees and bats
Among other things, the new plan - adopted by Carlton County commissioners earlier this month - does not allow any logging activity within 150 feet of a roost tree year-round.
Although bats hibernate in caves, sewers, rock cracks and other places where the temperature remains 45 degrees and above - Bernu called them "opportunists" - they give birth outside their hibernating habitats in the aforementioned "roost trees."
"The trees are important during the pup-rearing season," Bernu explained. "When the females give birth, it's outside the cave. They'll go find a suitable tree, the 'maternity roost tree,' it could be anything from 3 inches in diameter on up, but they usually like big, ugly, busted-up trees with lots of nooks and crevices that they can skootch down into. It keeps them close to their food source because they like to glean insects off of branches, as well as from the air."
Bernu said the pup will stay in the tree for a while, but the mother bats may also move the pup - on her back - to a better tree if she wants.
"Studies have shown that if she moves the pup, it's nearby. Usually 25 feet or so, up to a maximum of 150 feet," he said, adding that pup-rearing season is generally June 1 to July 31.
Bernu said the process was a unique and intense experience from start to finish, but he feels good about the plan and its research-based logging limitations.
"Taking care of our Minnesota forests means taking care of the other natural resources, like the bats that are dependent on them," Bernu said. "One cannot predict how far-reaching the effects of our local stewardship go."
Logging and bats
Carlton and Aitkin counties were also issued an "Incidental Take Permit," by the U.S. Fish and Wildlife Service. Approval of the habitat conservation plan and the permit authorizes the two counties to continue to manage county forestlands in a sustainable manner with modifications related to activities near maternity roosts and known places of hibernation over a 25-year project duration.
Although the counties' plan is approved, there are more measures to come. Bernu said the Minnesota DNR is working on its own plan to protect the bats, and they don't know what measures federal authorities will take.
The county's plan is designed to avoid or reduce unintentional "take" of the bat species. "Take," as defined under the Endangered Species Act, means to "harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or to attempt to engage in any such conduct."
County workers will paint the no-cut zone, so there should be no accidental logging, Bernu said. They get data on the roost tree areas from their own studies and others, including the DNR.
The county's own plan and permit have precedence over broader measures, but only on county-managed land. Bernu said the DNR plan may apply to private landowners, but he's not sure.
"This plan is a good thing," Bernu said. "And it's unique that two small counties did this. We are the first in the nation to do this for three bats. Others have done single bats, but they're all affected."
In a county news release, Fernholz noted the counties' actions have allowed them to stay a step ahead.
"Forest managers face lots of challenges and changing conditions," she said. "We have the choice to take a 'wait and see' attitude or to move forward and take action with the best available information and the knowledge of our professions. By conducting the bat surveys to gather additional information and then deciding to move forward with the [habitat plan] development, the counties have been able to reduce the risk of negative impacts to bats as well as to their operations and all of the environmental, social and economic benefits that sustainable forestry provides in Minnesota."